The present invention is directed to a method and apparatus for generating electrical energy. In particular, the invention provides a means by which the explosive energy provided by highly combustible propulsive sources, such as solid, liquid and gaseous propellants, can be used to generate sufficient electrical energy to power devices such as high energy spark generators, portable cardiac defibrilators, lasers and the like. The apparatus used can be compact, highly portable, and reusable. By providing a storage means and electrical discharge control, the method and apparatus can be adapted to power low energy devices over an extended period of time.
High energy systems require considerable electrical power in order to operate. Typically, energy levels in the hundreds of joules and greater are needed for devices such as defibrilators, lasers and the like. Such energy levels are commonly obtained by precharging one or more capacitors which are then quickly discharged into the device to be operated.
In view of the energy levels required, the capacitors are generally charged over a period of time from a constant power source, such as line current, which limits their portability and repeated use since the source must be present to provide a charge and/or recharge. Alternatively, storage batteries which are themselves heavy, have a finite life and must be periodically recharged by a separate power source are used.
Propellants, or explosive systems, exist in a wide range of physical forms from single compounds such as TNT to mixtures of substances and may be in solid, liquid or gaseous form. These compounds undergo rapid chemical reactions when ignited forming high pressure gases and releasing energy in the form of heat. Explosive materials are generally classified as either xe2x80x9clowxe2x80x9d or xe2x80x9chighxe2x80x9d depending on the rate of combustion. Low explosives burn at a rate of oxidation that is well below the speed of sound and produce gases at a manageable rate. These materials are used mainly as propellants for gun cartridges, solid fuel rockets and the like. High explosives burn at hypersonic speeds, i.e., 2,000 m to 8,500 m per second, so that the released gases form shock waves which shear and shatter nearby objects.
The purpose of propellants is to generate gases under pressure which can be used to provide thrust for a projectile. In most instances the gases are the means by which the energy released by combustion is converted to the work of pushing a projectile through the air. Other than for this purpose, the energy released does nothing else and is dissipated. The present invention seeks to provide a method whereby this energy can be used to generate electricity in a relatively simple manner and in an apparatus which can be readily carried by one individual. The invention further provides a means whereby electricity can be generated in high energy pulses for immediate use by high energy devices or stored and distributed in a controlled manner to low energy devices.
Electrical generators operate by rotation of a magnet within a coil to induce a current. This has been the principle on which electrical generators have worked since the electrical age began. The motive force to rotate the magnet in a generator has generally been provided by an external force such as steam, water, wind or the like in apparatus which has necessitated a large, fixed facility. Portable generators are usually powered either by a hand crank and have a limited output, or by a gasoline or diesel motor which is used to drive the shaft on which the magnet is mounted. Such generators are bulky, heavy, awkward and not easily portable. In addition, they require an fuel source that is also not easily transported. The output of the generator is in part governed by the speed of rotation of the magnet within the coil and in part by the windings in the coil and the field of the magnet. Where the windings and the magnetic field of two generators are identical, faster rotation of the magnet within the coil in one generator will produce a higher output than a slower rotation of the magnet within the coil of the other generator in accordance with the law of Energy=Velocity2.
By combining the motive force provided by explosive propellants with the principles of a generator, the inventors herein have devised a method and apparatus whereby these two features have been combined to provide a portable means to generate the energy levels needed to operate high energy systems in the field away from other sources of power. In addition, by providing a storage means, such as a bank of capacitors, and a controlling means, the high output of the method and apparatus of the present invention can be used to operate constant low level load systems over an extended period of time with periodic refreshing of the storage means.
It is an object of the present invention to provide a method and apparatus for generating electricity.
It is a further object of the present invention to provide a method and apparatus for generating electricity using the motive power generated by an explosive propellant.
It is a still further object of the present invention to provide a method and apparatus for the generation of electricity which is portable and which is capable of generating a high energy pulse suitable for use by high energy loads and which has a means for storing electricity for controlled release to low energy loads.
Further objects and advantages will become evident from the following description and claims.
In a basic configuration, the apparatus comprises a generator which operates by propelling a magnetic element through a series of electrical coils. The rapidly changing magnetic flux within the coils induces an electrical current in line with the existing laws for such machines. In this way, a single high energy electrical pulse can be created from a relatively simple apparatus. By utilizing appropriate power storage, control and discharge means, the generation of successive single pulses can be readily adapted to a variety of usable outputs including low energy continuous load devices as well as high energy pulse load devices.
In its simplest embodiment, the generator is constructed from copper coils wound around a bored barrel of non-magnetic, non-conductive material which is used to guide the magnetic element. Other conductor material may be used for the coils, including superconductors. The barrel is straight and of any suitable length to contain sufficient coils for the generation of the required amount of power to suit the final application or load. A simple receiver, sear and firing pin mechanism is attached to one end and is adapted to receive a cartridge comprising a casing housing a primer and propellant charge with the casing crimped to a magnetic element of a caliber corresponding to the barrel. A trigger mechanism activates the firing pin to fire the cartridge in the normal manner, thereby propelling the magnetic element along the barrel. In an alternative embodiment, the barrel may be circular so as to provide a continuous raceway for a trapped magnetic element thereby providing an effective infinite length to enable the extraction of the maximum amount of power from the passage of the magnetic element. In this instance, a xe2x80x9cblankxe2x80x9d cartridge may be used to provide the propellant gasses with appropriate means for admission of the pulse of gas into the barrel to propel the magnetic element.
The generator is unique in that it employs the pulse of energy created by the combustion of a ballistic propellant to drive a magnet through the coils thereby generating electrical energy which is extracted and used to power an electrical load. With a straight barrel, the length is such as to suite the particular application and may even be of sufficient length to slow the magnetic element sufficiently to permit its capture and reuse. Energy generated in an application utilizing typical existing firearm cartridge propellants may be in the region of 500 joules. Larger cartridges are capable of producing greater energy levels. When stored, the generated energy is available for discharge in comparatively short periods of time, about 1 millisecond, providing extremely high peak energy levels such as that required by laser flash lamps and cardiac defibrilators.
Thus, the present invention provides an apparatus for generating electrical energy comprising, an elongated conduit having a central bore adapted to receive a magnetic element for passage therethrough, a plurality of wire coils wound about the conduit and spaced along the length thereof, a magnetic element sized to pass through the bore, and means to propel the magnetic element through the bore, whereby passage of the magnetic element through the bore induces an electrical current in the coils.
The present invention also provides a method of generating electricity comprising propelling a magnetic pellet through at least one stationary tubular field coil.
The present invention further provides a method of generating electricity from high pressure combustion gases comprising, providing a plurality of field coils in substantially linear arrangement on a barrel having a central bore therethrough, providing a magnetic armature sized to pass through the bore, providing a means to propel the armature through the bore comprising a ballistic propellant capable of generating high pressure combustion gases directed against the armature in a direction corresponding to the linear arrangement of the field coils, and propelling the magnetic armature through the bore whereby the magnetic field of the armature passing across the field coils induces electrical current in the coils.